This is not an issue, human errors occurs at times.
If it is less than 30 days of submission of DS160, go back to the Consular Electronic Application Center (CEAC) website page for the DS-160. Click the tab for “Retrieve an Application.” Hopefully you took note of the application ID number from the DS-160 you submitted earlier, because you’ll need to enter that application ID number in the box. Then click the Retrieve Application button.
In the next dialog box, click “Create an Application.” Next, you’ll have to answer the security questions to get back into your form. Once you’re in, correct your mistake, then review everything, then electronically sign and submit the application. You will be given a new confirmation and bar code to print and bring to your interview.
If more than 30 days have gone by since you submitted the application with the mistake on it, you can upload that application back into CEAC, if you saved it on to your computer or other storage device. Go back to the CEAC website, click on DS-160, Online Nonimmigrant Visa Application, choose the consulate or embassy where you will be applying from the drop-down menu, and then click the “Upload an Application” tab. Choose the location of your saved file, and click the Upload Data button. After making your changes, save and submit the new application. You will be given a new confirmation and bar code.
If you never saved your original application, and it has been more than 30 days since you submitted it, you’ll need to start over. Go back on the CEAC website and fill in a new DS-160. Print the confirmation page for this new application.
If you used the first (incorrect) DS-160 submission to schedule your visa appointment or pay the visa application fee already, you will need to bring the confirmation pages from both the new (corrected) and the original (incorrect) DS-160 to your interview/dropbox.